The proposed ordinance is an attempt to close the loophole created when Florida banned more than 90 chemicals used in synthetic marijuana. County officials said that by the time those products were off the shelves, drugmakers had already adapted by concocting new, legal cocktails that are as dangerous as their predecessors.

"What we want to do is make sure that we took the opportunity to close those gaps to ensure those things don't come growing back," said Tim Burns, the county's director of Justice and Consumer Services.

In addition to banning synthetic marijuana, bath salts and kratom — a lesser-known substance that comes from a tropical plant — the ordinance would establish a five-person committee responsible for reviewing new products and possibly banning those as well.

Today, the Pinellas County Board of Commissioners will vote on whether to hold a public hearing on the proposed regulations.

Leo Calzadilla, who owns three tobacco shops in Pinellas County and is planning to open a fourth, said he would protest the ordinance. When state law banned a variety of products, he changed what he sold, he said. But the race to pass new ordinances and outfox manufacturers seems pointless to him, as well as bad for business.

"Herbal incense is sold as herbal incense," he said. "That's what it's intended for. … What people do with it is their prerogative."

Many of the synthetic marijuana products are labeled "not for consumption," said Pinellas County Sheriff Bob Gualtieri, adding that this was "intellectually dishonest."

Manufacturers know that teenagers buy their products intending to smoke or ingest them, he said. The drugs can cause extreme euphoria, as well as hallucinations and seizures. And there have been several high-profile instances in which teenagers died or were injured while under the influence of those substances.

Gualtieri said he is distributing letters to store owners, asking them to voluntarily drop the synthetic drugs from their inventories.

Randy Heine, owner of Rockin Cards & Gifts, a tobacco shop in Pinellas Park, said he would not object to banning synthetic marijuana, though this should be done at a state level, he said. But kratom is another matter.

Heine sells kratom leaves for smoking, kratom powder for making tea, and kratomite, a liquid concoction he described as a "relaxer."

"I've been selling it steadily for 30 years without a problem, zero, nada, nothing," he said. "There's minimal reports of problems, compared to coffee, aspirin, cigarettes, and nobody has died of this; it's just hysteria."

"I've got to confess I don't even know what it is," Gualtieri said. "It's not on my radar."

But Burns maintained that kratom is an emerging product, one that might not be well-known to law enforcement officials now, but is poised to replace the synthetic drugs the county is hoping to banish.

The county's proposed ordinance cites Thailand's decision to outlaw kratom, as well as the substance's inclusion on the Drug Enforcement Administration's list of drugs and chemicals of concern as reason for banning it in Pinellas.

County officials also have proposed new regulations that would require stores selling glass pipes and bongs to post large warning signs on the front of their buildings.

Anna M. Phillips can be reached at aphillips@tampabay.com or (727) 893-8779.